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The air that you breathe

Atualizado: 19 de nov. de 2020

English edit Carla Elliff

On 2018 September 3rd I received a ‘beautiful’ message congratulating me on Biologist Day (celebrated on this date in Brazil), which said: “Biology: thank you so much for NOT being a part of my life”. After realizing the NOT in this phrase, I couldn’t help but think about the paradox presented. Bio means life, so the human being that wrote this message was most likely alive and kicking, using up oxygen produced by other living beings through photosynthesis in order to maintain their cells working, while thinking how biology has nothing to do with his/her life…

Illustration by Joana Ho

What if I told you that a large portion of the oxygen consumed by this individual was produced by microalgae and cyanobacteria, organisms that are so small you can’t even see them? These microorganisms form a group we call phytoplankton, which in addition to supporting the whole marine food web, are also responsible for approximately 40% of all the oxygen produced annually on the planet, according to the American biological oceanographer Dr. Paul Falkowski. This means that while you can’t see microalgae and cyanobacteria when looking at the ocean, keep in mind that they can affect the oxygen and carbon cycles on Earth just as profoundly as our lush terrestrial plants. (Check out why algae are not plants).

But the importance of these minute critters does not stop there: life on our planet as it is today would not exist without cyanobacteria. Geologists have found that during the first half of the 4.6-billion-year existence of Earth there was no free oxygen in the planet’s atmosphere. Oxygen started to accumulate in our atmosphere only 2.4 billion years ago, thanks to the photosynthesis of ancestors of current cyanobacteria. Terrestrial plants only appeared 2 billion years ago, as explained by Dr. Falkowski, after the levels of atmospheric oxygen started to increase.

This means that all Homo sapiens sapiens, including yourself, of course, and all other life forms that depend on oxygen owe their existence largely to the appearance of a single cell able to obtain energy from the Sun to transform inorganic matter (carbon, water and other nutrients) into nourishment.

So, don’t think that Biology is not a part of your life just because you haven’t pursued a career in this subject! It is everywhere, including in the air you breathe!

To know more, check out this video.

I also recommend the song Spyro Gyro by Jorge Ben, just so you have proof that microalgae can even influence Brazilian music. ;)


Related post:



Paul G. Falkowski. The role of phytoplankton photosynthesis in global biogeochemical Cycles. Photosynthesis Research 39: 235-258. 1994.

Paul G. Falkowski. The power of plankton. Nature, 483: 17:20. 2012.

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